The Originals An encounter with a witch from his past causes trouble for Father Kieran (Todd Stashwick) at the reopening of St. Anne's Church. Charles Michael Davis, Claire Holt, Phoebe Tonkin and Joseph Morgan also star in this new episode. 8 p.m. KTLA

Marvel's Agents of S.H.I.E.L.D. Their pursuit of the Clairvoyant lands Coulson (Clark Gregg) and his team on a train that appears to be taking them to their deaths in this new episode. With Ming-Na Wen, Brett Dalton, Chloe Bennet, Iain De Caestecker and Elizabeth Henstridge, and Stan Lee makes a cameo appearance. 8 p.m. ABC

The Biggest Loser The contestants return for a reunion and to weigh in one last time, and one of the three finalists wins in the season finale. 9 p.m. NBC

Supernatural In this new episode, Sam and Dean (Jared Padalecki, Jensen Ackles) go under cover at a weight loss spa to investigate a series of murders. 9 p.m. KTLA